The subject matter disclosed herein relates to a check valve and, more particularly, to a flapper for a check valve.
In bleed systems where fluid pressure can be tapped off from either a high pressure stage compressor or a low pressure stage compressor, a check valve is needed to prevent the high pressure stage bleed air from backflowing into the low pressure stage compressor. This check valve often includes flappers that occupy closed positions when the high pressure stage bleed air has a higher pressure than the low pressure stage compressor, whereby the high pressure stage bleed air is prevented from backflowing into the low pressure stage compressor. These flappers open when the pressure of the low pressure stage compressor exceeds that of the high pressure stage bleed air.
When the flappers open, they often pivot at a relatively high angular velocity about a hinge pin and impact the check valve housing, which is normally provided with a compliant stop. Opposite sides of the compliant stop form contact areas with each of the flappers that are each limited in size and their respective ability to absorb the impacts. An interface between the hinge pin and the flappers, as well as an interface between the hinge pin and the check valve housing, are also subject to fatigue wear as opening and closing cycles of the flappers pivoting about the hinge pin are repeated over a period of time. Structurally withstanding the high opening velocities and the repeated impacts between the compliant stop and the flappers has, thus, proven to be challenging.